[R] writing function : can't find an object

[arnaud Gaboury]

Dear group,

Here is my function:


#return the daily PL for day y

PLDaily<-function(x,y)


{

#find elements in my directory with "LSCPos" in the name, keep the numeric
part in the name and
#create a list
  l<-gsub("\\D","",dir()[grep("LSCPos",dir())])

#select in the list the desired elements
  assign("sel",l[which(l==x):which(l==y)],envir=.GlobalEnv)
  #here is another solution  select<-l[l %in% seq(x, y)]
  
#first we need to create the Pos and Trad elements

  for (i in sel)  {

  assign(paste("Pos",i,sep=""),position(i),envir=.GlobalEnv)
  assign(paste("Trad",i,sep=""),trade(i),envir=.GlobalEnv)

                   }
#access elements in my environment
  posA<-get(paste(c("Pos",x),collapse=""))
  posB<-get(paste(c("Pos",y),collapse=""))
  av<-get(paste(c("Trad",y),collapse=""))
      
#apply some change on element columns then create only one data frame with
the three elements
  allcon<-ddply(rbind(av[,1:3],
transform(posA,prix=POSITION*SETTLEMENT,SETTLEMENT=NULL), 
          transform(posB, prix = -POSITION * SETTLEMENT, SETTLEMENT = NULL,
POSITION = POSITION * -1)),
          "DESCRIPTION",summarise,pl=sum(prix),quantity=sum(POSITION))  
     
#remove the date in $DESCRPTION and add a new column $SHORTDESCRIPTION
  allcon$SHORTDESCRIPTION<-sub('
[a-z]{3}/[0-9]{2}','',allcon$DESCRIPTION,ignore.case=TRUE)  
 
#read the contractvalue file
  value<-read.csv2("contractvalue.csv",sep=",",h=T,strip.white=T)
         
#merge "value" with "allcon", change some columns, then merge with PosB,
replace NA by zero and assign the final result to element PL
  zz<-merge(transform(merge(value,allcon,all.y=T),SHORTDESCRIPTION=NULL,
      VALUE=NULL,PL=-VALUE*pl,quantity=NULL),PosB,all.x=T,sort=F) 
  zz[is.na(zz)]<-0
  #PL<-zz[c(1,3,4)]
  assign(paste("DailyPL",y,sep=""),zz[,c(1,3,4)],envir=.GlobalEnv)
     
}

Here is what I get :

> PLDaily(100524,100525)
Error in as.data.frame(y) : object 'PosB' not found

> ls()
[1] "PLDaily"    "Pos100524"  "Pos100525"  "position"   "sel"
"Trad100524" "Trad100525" "trade"

Why R can't find "PosB" ?

TY for your help.